How to choose the right power connector

System design is becoming increasingly miniaturized, but the demand for power supply is growing, which poses a huge challenge for design engineers. This means that the power connector must accommodate two contradictory necessary conditions at the same time, which means that while increasing the power supply, the design must also be more compact. When screening the dazzling array of power connectors on the market, it is even more difficult to know how to proceed. Taking the key characteristic of rated current as an example, it contains a lot of knowledge.

Rated current is the amount of current that causes a specific temperature rise in the female terminal, usually 20 ℃ or 30 ℃. To use this data correctly, in addition to understanding its testing methods, one must also pay attention to its testing environment. For example, some simply test a pair of connected female terminals and male pins without installing them inside the casing. As is well known, factors that affect the temperature rise of connectors include contact resistance, current flow, and heat dissipation channels. In practical applications, male and female terminals are installed inside the housing. Therefore, the cooling channels are greatly reduced. In addition, multiple contact pairs are generally used simultaneously, and the rated current peak cannot be set as the working current of the connector. From a production perspective, traditional power connectors are mostly machined on lathes. Based on the increasingly mature stamping technology, a new generation of stamped power connectors has been derived. In contrast, lathe machining has a simpler process and shorter tool setting time, making it a more flexible production technology. Although the stamping process is relatively expensive, its cost is comparable to lathe machining when put into mass production, especially since stamping technology allows for localized electroplating, which is an option that lathe machining cannot provide. From a quality perspective, stamping ensures a certain level of quality stability in long-term mass production, which cannot be compared to lathe machining.

From the perspective of assembly, the methods of circuit board assembly include crimping, surface pasting or welding; The methods of cable assembly include screw connection, welding, winding, rolling, and IDC (commonly known as puncture connection or insulation displacement connection). To choose the appropriate connector, not only should the price of the connector be considered, but the more important factor is the appropriate assembly technology. Welding connectors are naturally cheaper than surface mount and crimping connectors because they do not require high-temperature resistant plastic shells or special crimping areas for the pins. However, if all the components on the single board are surface mount, choosing surface mount power connectors is still a more cost-effective decision. In terms of wiring, screw connections, welding, and winding must be manually assembled, while crimping and IDC can use assembly equipment on the market to quickly and accurately assemble connectors and cables. Compared with crimping, IDC has stricter requirements for cable size. The size and hardness of cable conductors and insulation layers must comply with the specifications of relevant IDC connectors to avoid damaging the connectors and ensure ideal electrical connections between the cables and connectors. If applied in high vibration working environments, rolled cable connectors should be selected. Other factors that need to be considered include the working environment temperature and the consideration of whether to use high-temperature resistant cables.